1. Technical Field
The present application relates to a wing and especially to an improved method and apparatus for landing a wing.
2. Background of Related Art
Hang gliders allow manned flight without the expense or restrictions of powered flight. These gliders are aerodynamically designed such that their lift-to-drag ratio (commonly known as glide ratio) is greater than about 10:1 such that the glider is capable of suspending a flyer for several hours under the proper atmospheric conditions. Hang glider designs range from the popular delta wing design commonly known as a Rogallo wing and intermediate gliders with glide ratios of about 10:1 with docile characteristics to competition gliders with glide ratios as high as 13:1, but with less stable characteristics. The original Rogallo wing (about 45.degree. sweep) had a glide ratio of about 4:1, and modem Rogallo wings (about 30.degree. sweep) have a glide ratio of about 10:1.
The Rogallo wing design largely resembles a traditional kite with a keel, cross members, and diverging leading edge members. Another hang glider design generally similar to the Rogallo wing is disclosed in U.S. Pat. No. 4,116,406 which issued to Hamilton on Sep. 26, 1978. This glider has a double surface fabric airfoil forming an envelope, disposed around a Rogallo frame. This airfoil is inflated during flight as air enters an opening in the nose and exhausts through nozzles in the underside along the trailing edge. Inflating the wing improves its lift at lower air speeds. This hang glider, however, is manually controlled via a weight shift control bar by a flyer harnessed to the glider and is only usefull for manned flights and not for operations such as air drops of food, supplies, etc., where manned flights are either too dangerous or impossible.
Another hang glider design similar to the Rogallo wing and having a collapsible airfoil is disclosed in U.S. Pat. No. 4,116,407 to Murray. This hang glider comprises a wing which includes leading edge members, a keel and cross members in a traditional delta wing design. The wing further includes upper and lower flexible membranes, a first connector for attaching the upper flexible membrane to the upper aft section of the leading edge member and a second connector for attaching the lower flexible membrane to the lower aft section of the leading edge member. The flexible membranes are also joined together rearwardly of the leading edge member. At least one of the first and second connectors includes a track for receiving a member carried by one of the flexible membranes. The member cooperates with the track to attach the flexible membrane to the leading edge member. The leading edge members are also capable of being pivoted inwardly toward the keel to collapse the wing.
Parachutes, on the other hand, can and have been utilized for air drops of food, supplies, etc., in remote locations where landing an airplane is either impossible or dangerous. Although these parachutes are useful in reducing the ground impact of the dropped load, it is difficult to ensure the parachute reaches the targeted area. Depending upon the precise parachute release time, the atmospheric conditions during release and flight, and release altitude, the parachute may either reach its target or drift up to about 15 miles or more off course.
Patent application Ser. No. 08/156,322. (Issued as U.S. Pat. No. 5,474,257) which is commonly assigned and is hereby incorporated by reference, discloses a deployable wing comprising a double membrane fabric sail having an upper section disposed above and joined to a lower section, the sail having a leading edge with a front point, a trailing edge, and wing tips. The deployable wing further includes an internal structure disposed between the upper section and the lower section, the internal structure having two leading edge spars with a first end and a second end, said first ends pivotally connected together at approximately the front point, a keel spar connected to and disposed between the leading edge spars at the front point and extending rearward toward the trailing edge, and at least two cross spars pivotally attached to both the leading edge spars and a sliding mechanism which traverses along the keel. The wing also includes a plurality of fabric ribs disposed between and connected to the upper section and the lower section, the fabric ribs defining the shape of the fabric sail when inflated and have at least one slot through which the cross spars extend from the keel spar to the leading edge spars and ribs; and a ram air intake located on said leading edge at the stagnation point of the wing which inflates the wing during operation. The deployable wing attains a glide ration up to or exceeding about 12:1, and greater than 8:1 with typical payloads of about 1,000 lbs. for a 30 ft. wing.
The wing disclosed in application U.S. Pat. No. 5,474,257 is remotely controllable, allowing for both unmanned flight and accuracy in reaching a targeted area thereby making the wing useful for article recovery and delivery. The deployable wing is, however, the first of its type and it has been found that an improved apparatus and method for landing of such a wing is desired.
The present application therefore provides an improved apparatus and method for landing of a wing, preferably by parachutes.